Peke - Good question, I don ot use a buffer in my pvc pipe. I am not concerned whether the rebar makes noise. If the glue job is good then the pipe should be tightly sealed. The rebar shifting in the pipe downward acts as a stike indicator. The shift causes the jug to be cocked at an angle thus indicating that a fish is on or the jug has had a hit. If the water is really rough then the rebar might shift causing a false reading.

Josh - Personally the biggest cat I have caught on this style of jug setup is around 25 pounds.